Identification of Endoglin as a Functional Marker That Defines Long-Term Repopulating Hematopoietic Stem Cells

• Published in: Proceedings of the National Academy of Sciences - PNAS 2002-11, Vol.99 (24), p.15468-15473
• Main Authors: Chen, Chang-Zheng, Li, Min, de Graaf, David, Monti, Stefano, Göttgens, Berthold, Sanchez, Maria-Jose, Lander, Eric S., Golub, Todd R., Green, Anthony R., Lodish, Harvey F.
• Format: Article
• Language: English
• Subjects: Adult stem cells; Animals; Animals, Congenic; Antibodies; Antigens, CD; Biological Sciences; Biology; Biomarkers; Blood cells; Bone marrow; Bone marrow cells; Bone Marrow Cells - cytology; Cell Lineage; Colony-Forming Units Assay; Complementary DNA; DNA, Complementary - genetics; Endoglin; Female; Flow Cytometry; Gene Expression Profiling; Gene Expression Regulation; Genes; Hematopoietic Stem Cell Transplantation; Hematopoietic stem cells; Hematopoietic Stem Cells - chemistry; Hematopoietic Stem Cells - cytology; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, SCID; Mice, Transgenic; Oligonucleotide Array Sequence Analysis; Polymerase Chain Reaction - methods; Radiation Chimera; Receptors, Cell Surface; RNA; Stem cells; Subtraction Technique; Transgenic animals; Vascular Cell Adhesion Molecule-1 - genetics; Vascular Cell Adhesion Molecule-1 - physiology
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.202614899

We describe a strategy to obtain highly enriched long-term repopulating (LTR) hematopoietic stem cells (HSCs) from bone marrow side-population (SP) cells by using a transgenic reporter gene driven by a stem cell enhancer. To analyze the gene-expression profile of the rare HSC population, we developed an amplification protocol termed "constant-ratio PCR," in which sample and control cDNAs are amplified in the same PCR. This protocol allowed us to identify genes differentially expressed in the enriched LTR-HSC population by oligonucleotide microarray analysis using as little as 1 ng of total RNA. Endoglin, an ancillary transforming growth factor β receptor, was differentially expressed by the enriched HSCs. Importantly, endoglin-positive cells, which account for 20% of total SP cells, contain all the LTR-HSC activity within bone marrow SP. Our results demonstrate that endoglin, which plays important roles in angiogenesis and hematopoiesis, is a functional marker that defines LTR HSCs. Our overall strategy may be applicable for the identification of markers for other tissue-specific stem cells.